EXPLANATORY STATEMENT
CIVIL AVIATION ACT 1988
CIVIL AVIATION REGULATIONS 1988
DIRECTIONS UNDER SUBREGULATIONS 235 (2) AND 215 (3)
TAKE-OFFS ON WET RUNWAYS BY DHC 8-202 AIRCRAFT
Section 98 of the Civil Aviation Act 1988 empowers the Governor-General to make regulations.
Subregulation 235 (2) of the Civil Aviation Regulations 1988 (CAR 1988) provides that the Civil Aviation Safety Authority (CASA) may give directions setting out the manner of determining a maximum weight for an aircraft, in respect of a proposed flight, that the gross weight of the aircraft must not exceed at take-off.
Subregulation 235 (4) provides that an aircraft must not take off, or attempt to take off, if its gross weight is greater than its maximum take-off weight or a lesser weight determined in accordance with subregulation 235 (2).
The instrument contains directions under subregulation 235 (2) for determining a maximum weight that DeHavilland Canada DHC 8-202 aircraft, operated by Surveillance Australia Pty Ltd (ACN 050 021 308) (the operator), must not exceed while taking off from a wet runway. The operator conducts coastal surveillance operations primarily from remote locations.
Section 20.7.1B of the Civil Aviation Orders (CAOs) sets out CASA’s directions for the purposes of subregulation 235 (2). Paragraph 4.1 of section 20.7.1B of the CAOs, provides that the maximum weight that an aeroplane to which the section applies may not exceed at take-off is the least of the weights determined in accordance with subparagraphs 4 (1) (a) to (d). Under subparagraph 4.1 (a), one of those weights is a weight calculated by reference to the take-off distance and accelerate-stop distance required. The calculation has to be made in accordance with paragraphs 6.1 and 6.2 of section 20.7.1B of the CAOs.
The approved flight manual for the DHC 8-202 aircraft supplies data that permits the pilot in command to determine the maximum weight of the aircraft at which the take-off distance required is equal to or less than the take-off distance available. The data applies to take-offs from dry runways. Under subparagraph 6.2 (a) of section 20.7.1B of the CAOs there is a requirement for the aircraft to be at 35 feet above the surface at the end of the take-off distance available.
In the case of wet runways, the accelerate-stop distance required (in the event of an rejected take-off) is greater than on dry runways unless a lower take-off decision speed (V1 speed) is used. The DHC 8-202 Flight Manual supplies, at Supplement No. 51 (Supplementary Performance Information for Takeoff on Wet Runways) take-off data for wet runways, with a reduced V1 speed, that provides for an obstacle clearance, at the end of the take-off distance available, of 15 feet. This would not comply with the height requirement of 35 feet in paragraph 6.2 of section 20.7.1B of the CAOs.
Therefore, to allow the use of manufacturer’s wet runway performance data for DHC 8‑202 aircraft operated by the operator, a direction under subregulation 235 (2) of CAR 1988 is required. This direction will modify directions set out in subparagraph 4.1 (a) of section 20.7.1B of the CAOs by modifying the provisions of subparagraph 6.2 (a). In particular, it provides that accelerate-stop and take-off distances established under this direction may be used under subparagraph 4.1 (a) for calculating take-off weight limitations as if established in accordance with subparagraph 6.2 (a). The calculation of take-off distance must not include clearway.
The instrument also contains a direction under regulation 215 that the operator must include the wet runway procedures in its operations manual.
Under regulation 5A of CAR 1988, a “prescribed direction” that affects the operation of anything in a CAO is a disallowable instrument. The instrument is “a prescribed direction” that affects the operation of subsections 4 and 6 of section 20.7.1B of the CAOs.
The instrument has been issued by the Deputy Chief Executive and Chief Operating Officer, a delegate of CASA, appointed under regulation 7 of CAR 1988.
[Instrument Number: CASA 148/04]